Bug 985012

During testing luci vs. python-weberror in FIPS mode [bug 746118],
I've discovered that URLs like these:

  https://${HOST}:8084/cluster/${CLUSTERNAME}/failovers
  https://${HOST}:8084/cluster/${CLUSTERNAME}/fences
  https://${HOST}:8084/cluster/${CLUSTERNAME}/resources
  https://${HOST}:8084/cluster/${CLUSTERNAME}/services

lead to Error 500: We're sorry but we weren't able to process this request
(which involved Beaker middleware and the FIPS-related bug caused emitting
plain "Internal Server Error").


The tracebacks follow this pattern:

File '/usr/lib/python2.6/site-packages/pylons/wsgiapp.py',
line 125 in __call__
  response = self.dispatch(controller, environ, start_response)
File '/usr/lib/python2.6/site-packages/pylons/wsgiapp.py',
line 324 in dispatch
  return controller(environ, start_response)
File '/usr/lib64/python2.6/site-packages/luci/controllers/root.py',
line 53 in __call__
  return BaseController.__call__(self, environ, start_response)
File '/usr/lib64/python2.6/site-packages/luci/lib/base.py',
line 30 in __call__
  return TGController.__call__(self, environ, start_response)
File '/usr/lib/python2.6/site-packages/pylons/controllers/core.py',
line 221 in __call__
  response = self._dispatch_call()
File '/usr/lib/python2.6/site-packages/pylons/controllers/core.py',
line 172 in _dispatch_call
  response = self._inspect_call(func)
File '/usr/lib/python2.6/site-packages/pylons/controllers/core.py',
line 107 in _inspect_call
  result = self._perform_call(func, args)
File '/usr/lib/python2.6/site-packages/tg/controllers.py',
line 857 in _perform_call
  self, controller, params, remainder=remainder)
File '/usr/lib/python2.6/site-packages/tg/controllers.py',
line 172 in _perform_call
  output = controller(*remainder, **dict(params))

-- ONE OF --

# failovers
File '/usr/lib64/python2.6/site-packages/luci/controllers/cluster.py',
line 816 in failovers
  if not self.model.getFailoverDomainByName(failovername):
AttributeError: 'NoneType' object has no attribute 'getFailoverDomainByName'

# fences
File '/usr/lib64/python2.6/site-packages/luci/controllers/cluster.py',
line 936 in fences
  if not self.model.getFenceDeviceByName(fencename):
AttributeError: 'NoneType' object has no attribute 'getFenceDeviceByName'

# resources
File '/usr/lib64/python2.6/site-packages/luci/controllers/cluster.py',
line 516 in resources
  self.model.getResourceByName(resourcename)
AttributeError: 'NoneType' object has no attribute 'getResourceByName'

# services
File '/usr/lib64/python2.6/site-packages/luci/controllers/cluster.py',
line 644 in services
  if not self.model.getService(servicename):
AttributeError: 'NoneType' object has no attribute 'getService'

-- === ---


This should be captured in the earlier processing and the error note
should be emitted accordingly.

Sidenote: what are the states leading to model attribute being None?
I reproduced the issue with node-less cluster, unfortunately don't
recall if this is artificial degenerate case or something one can
set up deliberately.